More stuff according to article

packages/backend/.eslintrc.js

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+module.exports = {
+  rules: {
+    'no-console': 0,
+  },
+};

packages/backend/src/index.ts

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+/*
+ * Copyright 2020 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Required External Modules
+ */
+
+import * as dotenv from 'dotenv';
+import express from 'express';
+import cors from 'cors';
+import helmet from 'helmet';
+
+dotenv.config();
+
+/**
+ * App Variables
+ */
+
+if (!process.env.PORT) {
+  process.exit(1);
+}
+
+const PORT: number = parseInt(process.env.PORT as string, 10);
+
+const app = express();
+
+/**
+ *  App Configuration
+ */
+
+app.use(helmet());
+app.use(cors());
+app.use(express.json());
+
+/**
+ * Server Activation
+ */
+
+const server = app.listen(PORT, () => {
+  console.log(`Listening on port ${PORT}`);
+});
+
+/**
+ * Webpack HMR Activation
+ */
+
+type ModuleId = string | number;
+
+interface WebpackHotModule {
+  hot?: {
+    data: any;
+    accept(
+      dependencies: string[],
+      callback?: (updatedDependencies: ModuleId[]) => void,
+    ): void;
+    accept(dependency: string, callback?: () => void): void;
+    accept(errHandler?: (err: Error) => void): void;
+    dispose(callback: (data: any) => void): void;
+  };
+}
+
+declare const module: WebpackHotModule;
+
+if (module.hot) {
+  module.hot.accept();
+  module.hot.dispose(() => server.close());
+}

packages/backend/webpack.config.ts

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+/*
+ * Copyright 2020 Spotify AB
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+const webpack = require('webpack');
+const path = require('path');
+const nodeExternals = require('webpack-node-externals');
+
+module.exports = {
+  entry: ['webpack/hot/poll?100', './src/index.ts'],
+  watch: true,
+  target: 'node',
+  externals: [
+    nodeExternals({
+      whitelist: ['webpack/hot/poll?100'],
+    }),
+  ],
+  module: {
+    rules: [
+      {
+        test: /.tsx?$/,
+        use: 'ts-loader',
+        exclude: /node_modules/,
+      },
+    ],
+  },
+  mode: 'development',
+  resolve: {
+    extensions: ['.tsx', '.ts', '.js'],
+  },
+  plugins: [new webpack.HotModuleReplacementPlugin()],
+  output: {
+    path: path.join(__dirname, 'dist'),
+    filename: 'index.js',
+  },
+};